There’s a rather good Wikipedia page about this
The Hype Cycle is a branded graphical presentation developed and used by American Information Technology (IT) research and advisory firm Gartner for representing the maturity, adoption and social application of specific technologies. The Hype Cycle provides a graphical and conceptual presentation of the maturity emerging technologies through five phases.
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Van Lente, H., Spitters, C., Peine, A., 2013. Comparing technological hype cycles: towards a theory. Technological Forecasting and Social Change 80 (8), 1615–1628.